Small tap-off terminal



May 14, 1963 H. STROEBEL SMALL TAP-OFF TERMINAL Filed Oct. 21. 1960 IN VENTOR ATTORNEY United States Patent 3,090,029 SMALL TAP-OFF TERMINAL Hermann Stroebel, Stuttgart-Schonberg, Germany, assign- Or to Richard Hirschmann Radioteclmisches Werk, Esslrngen (Neckar), Germany, a firm Filed Oct. 21, 1960, Ser. No. 64,107 Claims priority, application Germany Oct. 30, 1959 1 Claim. (Cl. 339255) The invention rel-ates to tap-off terminals for use with small structural elements such as transistors and the like.

Small structural elements, for example transistors, having printed circuits and capable of being assembled in narrow spaces for fabricating handy pocket-size apparatus, are growing rapidly in importance in the electronics arts. However, the contacts for the connections are closely spaced on the structural elements and thus prevent the application of conventional tap-off terminals, for measuring and testing purposes, since they would give rise to short circuits with the adjoining contacts. This requires using very small tap'off terminals.

The present invention, in brief, is to provide very small tap-01f terminals of suitable construction. To this end, according to a practical embodiment of the present invention, the terminal has a total length of only 17 mm. and a maximum width of 3 mm. Terminals of known construction cannot be made with such small dimensions, at least not economically by mass production methods.

This object is accomplished in accordance with the present invention by means of a tap-oif terminal in which the two terminal legs, being constructed as two-armed levers, are rotatable relative to each other in known manner, said terminal being characterized by the fact that the terminal legs, each consisting of a grip portion and a clamp portion, are held together by a spring which is passed through elongated openings in the two grip portions of said terminal legs and are caused to rest under pressure against the outside of the clamp portions thereof. The spring is suitably recessed in grooves or notches pro- 'vided in said clamp portions to prevent it from sliding off.

According to a specific preferred embodiment of the present invention the tap-oil terminal has a spring of the shape of a quadrangle of which two sides extend along the terminal legs, whereas a third side extends through elongated openings in the two grip portions of the terminal legs. The fourth side has an opening through which are passed the clam-ping portions of the terminal legs. The ends of the spring will thus rest under pressure against the outside of the clamping portions.

Another suitable embodiment of the tap-off terminal according to the present invention comprises certain means for controlling the relative rotation of the terminal legs about a predetermined axis. Each of the longitudinal sides thereof has a tongue bent off at 90 in such a way that each terminal leg is provided with a pair of oppositely positioned tongues. The pair of tongues of the one terminal leg lies between the tongues of the other terminal leg and exhibits circular faces which are urged by the spring into a suitable recess between the lateral tongues of the other terminal leg. One of the terminal legs is now capable of being rotated relative to the other on the circularly extending faces of its pair of tongues. This arrangement is very simple and inexpensive to manu facture, since it does not require an axis of rotation and any additional parts. The entire terminal consists of only three parts, i.e. the two terminal legs and the spring which can be assembled without further fastening means.

In the case of a small tap-oil terminal, the two clamping surfaces between which the parts to be seized are grasped must, of necessity, be also small. However, in order to ensure a good contact and a firm hold of the 3,090,029 Patented May 14, 1963 terminal on the parts that are grasped by it, the clamping surface of one of the terminal legs is concavely bent in the direction of the axis of rotation of the terminal legs, whereas the clamping surface of the other terminal leg is provided with teeth and/or notches extending parallel to the axis of rotation.

The grip portion of one of the terminal legs can be provided with a socket for a clamping or soldering connection of a feed line.

The invention will be more readily understood from the following detailed description and the accompanying drawing, of which,

FIG. 1 is a perspective view and FIG. 2 an elevation view, partly in section, of the tap-off terminal constructed in accordance with the present invention.

Referring to the drawing, the tap-off terminal shown therein consists of two terminal legs 1 and 2 which are shaped as two-armed levers, and a spring 3 made of round wire.

Each of the two longitudinal sides of both terminal legs 1 and 2 has a tongue 4 or 5 bent off at so that each terminal leg will display a pair of oppositely positioned tongues. The pair of tongues 5 is introduced between tongues 4 and lies with its circularly extending faces in a suitable recess 6 in terminal leg 1.

The spring has a quadrangular shape. Two legs 7 and 8 of the spring extend along the terminal legs 1 or 2. A cross-piece 9 between the legs 7 and 8 of the spring is passed through two longitudinal openings 10 and 11 in the grip portion 12 or 13 of terminal legs 1 or 2.1. The free end 14 of spring leg 7 is bent off at about 90 and is inserted with its point in a recess 15 in the clamping portion 16 of terminal leg 1. The free end of spring leg 8 lies in a notch 17 in the clamping portion 18 of terminal leg 2'.

For assembling the tap-oft terminal it is merely necessary to slide the pair of tongues 5 between the pair of tongues 4, insert the cross-piece 9 of spring 3 into longitudinal openings 10 and -11 and swing the legs 7 and 8 of the spring onto the terminal legs 1 or 2 until the free ends thereof engage the recess 15 of the notch 17. As a result, the terminal legs 1 and 2 are held by spring 3 in a manner that will permit relative rotation but not displacement thereof.

The clamping portion 16 is provided in its clamping surface with teeth 19 which extend parallel to the axis of rotation of the terminal legs, whereas the clamping surfiace 20 'of clamping portion 18 is concavely bent in the direction of rotation of the legs. The grip portion 12 of the terminal leg 1 is bent in the shape of a socket in which a feed line can be clamped or secured by soldering.

I claim:

Small tap-01f terminal comprising two terminal legs each having a grip portion and a clamping portion and being rotatable about a predetermined axis relative to each other as two-armed levers, and a spring that holds the two terminal legs together passing through longitudinal openings in the two grip portions and resting under pressure against the outside of the two clamping portions, the two longitudinal sides of the two terminal legs each having a tongue bent off at 90, the pair of tongues of one terminal leg lying between the tongues of the other terminal leg and displaying circularly extending faces which are urged by the spring into a recess between the lateral tongues of the second terminal leg so that the first terminal leg is capable of being rotated relative to the second on the circularly extending faces of its pair of tongues.

(References on following page) UNITED STATES PATENTS Luther Mar. 29', 1910 Kennison Nov. 9, 1920 5 Isele Apr. 27, 1926 Darby Apr. 7, 1936 4 Thompson et a1. Oct. 28, 1941 Roark July 5, 1949 Pechtel Nov. 11, 1952 Homand July 22, 1958 FOREIGN PATENTS Sweden Apr. 21, 1953 

